Molecular imaging is a new discipline that makes possible the noninvasive visualization of cellular and molecular processes in living subjects. Here we will adopt the reporter gene and reporter probe imaging technique (developed initially for cancer researchers) to solve a different important problem in cardiology (i.e., understand pharmacokinetics and biodistribution of cardiac stem cell therapy). In particular, we will develop and validate various reporter genes that will enable us to image fate of cardiac stem cells (CSC) in vivo. We will use clinical positron emission tomography and computed tomography (PET/CT) and magnetic resonance imaging (MRI) to track the survival, proliferation, and function of transplanted cells in pre-clinical large animal models. The information gathered from these studies should prove instrumental for marrying molecular imaging with clinical stem cell therapy in the future. PUBLIC HEALTH RELEVANCE: Coronary artery disease (CAD) is a progressive disease with high morbidity and mortality rates in the US. Following myocardial infarction (MI), the limited ability of the surviving cardiac cells to proliferate renders the damaged heart susceptible to unfavorable remodeling processes and morbid sequelae such as heart failure. For now, heart transplantation is the only viable treatment option for end-stage heart failure patients. Given the persistent shortage of donor heart organs, stem cell therapy has emerged as a promising candidate for treating ischemic heart disease because it provides a virtually unlimited source of cardiomyocytes, endothelial cells, and other differentiated cell types to be used in all stages of cardiac repair. Thus, imaging cell fate after transplantation is a high priority in both basic research and clinical translation. In order for cell based therapy to truly succeed, we must be able to track the location(s) of delivered cells, the duration of cell survival, and any potential adverse effects. Our major goals for this grant are to develop and validate novel reporter gene & reporter probe techniques for tracking fate of cardiac stem cells (CSCs). Importantly, the information we obtain here on detection sensitivity and the overall experience we gain will be extremely valuable for eventual clinical translation of cardiac molecular imaging in the future.